The present invention is related to automatic lumber stacking apparatus with layer spacing stickers situated between the layers of boards.
In the lumber industry, boards that have been freshly cut from logs are generally sorted and stacked for drying in a dry kiln. During the stacking operation, stickers or elongated wooden slats are placed transversely between layers at spaced intervals. Usually, the stickers have lengths equal to the width of the stack and are situated transverse to the boards in the stack. The stickers are spaced at longitudinal intervals along the layers of boards to separate the layers and enable drying gases within the kiln to circulate through the stack and uniformly dry the boards.
In many stacking operations today, stickers are placed manually between the layers of boards. Such manual placement of stickers is costly, tedious and often dangerous.
Automatic sticker placing equipment has been developed although many such forms of this equipment can only be justified in the largest of operations. Most existing automatic sticker placing apparatus include individual sticker magazines adajcent each sticker placement station for storing the stickers to be placed between layers of boards. Loading these magazines often requires the full attention of at least one worker while another is required to operate the stacking machine. Furthermore, it is frequent that such magazines are situated adjacent one side of the stack that is opposite to the lumber stacking apparatus. Therefore, such placement apparatus requires additional space and operating equipment.
U.S. Pat. No. 3,904,044 granted to applicant, Sidney L. Lunden, on Sept. 9, 1975 describes a sticker placing device for lumber stacking apparatus that automatically delivers stickers from a single magazine to successive locations along the length of a layer of boards. The sticker magazine and sticker indexing conveyor are located behind the stacking apparatus and require additional intermediate handling prior to placement beneath a layer being carried to the stack. The selected group of spaced stickers is lifted from the rear sticker supply conveyor and moved forward to an intermediate position between the sticker conveyor and the lumber stack. Then, in another step, the stickers are lifted to spaced locations below a layer of boards and finally transferred over and onto the stack. This apparatus is entirely effective and greatly reduces the necessary equipment and space previously required for auxiliary automatic sticker placing apparatus.
However, the applicant has discovered a substantial improvement which greatly simplifies the apparatus and increases the sticker placement reliability. Such improvement is the subject of this application. Additionally the lumber stacking machine is produced with fewer component parts and will operate in a relatively smaller area.